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Thread: 440 Ring gap?

  1. #1
    Race, wreck, repeat delagem's Avatar
    Join Date
    Aug 2006
    Homer, NY

    440 Ring gap?

    I'm tearing into the motor on my '89 440 to find out why I don't have very good compression, about 80/90. I pulled the jug and pistons, took off the rings, and checked the clearance between the piston and cylinder w/ a feeler gauge, shows .06mm, which is fine according to my service manual.

    The problem is, my manual doesn't list ring end gap! I checked it, and came up with .7mm, which is way big I think. Does anyone know what this gap should be?

    I'm a little concerned about the compression, as the piston isn't the problem, and I'm using the same battery and compression gauge in another 440, where it's around 130/130. Could just that ring gap cause this?

  2. #2

    Join Date
    Apr 2005
    0.2-0.4mm standard value
    0.7mm service limit
    Last edited by 1FastTrespiper; 01-13-2007 at 06:46 PM. Reason: correction

  3. #3

    Join Date
    Apr 2005
    While your at it pull the flywheel cover. If the flywheel and the inside of the flywheel cover look oiley, the front crank seal is bad.

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